(1) Field of the Invention
The invention relates to a laser capture microdissection system and an electric moving stage thereof, especially relates a laser capture microdissection system and an electric moving stage thereof for serving to capture the nanoscale particles or biological samples, such as the nanoscale tissue cell.
(2) Description of the Prior Art
Following the advancement and accumulation of the optoelectronics knowledge as well as the progress in the optoelectronics technology, engineers and scientists are urged to exploit and employ the laser technology together with precise electric position control into nanoscale so that an user-friendly simple opto-electric positioning mechanism can be worked out for capture, separation or dissection of the target cell specimen via laser technology in simple, quick and precise manner.
Currently, laser systems for capture, separation or dissection of the target cell specimen can be roughly categorized into three generations chronologically: 1. Primeval Laser Capture Microdissection (LCM); 2. Laser Microdissection and Pressure Catapulting (LMPC); and 3. Leica AS LMD. Wherein, the first generation Laser Capture Microdissection (LCM) is still most popularly adopted for following reasons: well known due to earliest development; comprehensive existing information and documents accumulated about sample preparation from experienced users; low price relatively; and easy and quick operation in dissection process.
Refer to FIG. 1 for the schematic view showing the structural configuration of a conventional laser capture microdissection system 100. The conventional laser capture microdissection system 100 mainly includes an inverted microscope 110, a laser diode 120, a fiber probe 130, an ethylene vinyl acetate (EVA) transfer membrane 140 and a glass slide 150. The inverted microscope 110 has a microscopic stage and an objective. The practical operation is described as below: Firstly, attach the EVA transfer membrane 140 over a histological tissue slice 200, then place the tissue slice 200 on the microscopic stage of the inverted microscope 110 for being observed by the suitable objective; Secondly, shift the tissue slice 200 to identify target cells (not shown) of interest in a target area of the microscope field; Thirdly, set up the laser diode 120 and the fiber probe 130 at suitable locations so that a laser beam, which is illuminated from the laser diode 120 with high optical energy density formed via the fiber probe 130, irradiates the EVA transfer membrane 140 over the target cells of interest to form a light spot 142; Fourthly, the EVA transfer membrane 140, which is heated up to its melting point via absorption the optical energy of the irradiated laser beam from the laser diode 120, becomes strong adhesive and enabled to bind the target cells of interest.
Finally, tear the EVA transfer membrane 140 away from the tissue slice 200. Because the melted adhesive binding force between the target cells and the EVA transfer membrane 140 is greater than the attaching force between the target cells and the peripheral tissue, the target cells with the EVA transfer membrane 140 is sliced from the tissue slice 200 to get apart.
However, the size of most plant cells is between 100 to 200 micrometer, and the size of the animal cell is about one-tenth of the size of the plant cell. For getting the captured result better, the diameter of the target cell is at least lager than or equal 5 micrometer. When the diameter of the target cell is smaller than 5 micrometer, the captured parts of cell inevitably contain the tissue close to the target cell, probably contaminating the target cell.
Refer to FIG. 2, for the schematic view showing a stage 250 of a conventional laser capture microdissection system 100. The conventional stage 250 provides a place for laying the glass slide 150, the EVA transfer membrane 140 and the tissue slice 200 thereon. During dissecting process, the target cells should be centered in a target area of the microscope field (dashed circle) for being inspected the light spot 142, which appears on the EVA transfer membrane 140 irradiated by a low power laser beam from the laser diode 120 through fiber probe 130 in the inverted microscope 110.
However, because of no fine tuning feature for precise movement of the conventional stage 250, the alignment of the fiber probe 130 with the target cells is a very difficult and hours time-consuming task so that the overall microdissection process becomes very slow.